New Holland 40 Series Repair Manual page 31

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Valve Seat Specifications, Figure 13.
1, Valve seat angle:-
lntake
=
30.0°-30.30°
Exhaust
=
45.0°-45.30°
2, Valve seat width:-
lntake
=
0.078-0.098 in
(1.9-2.4mm)
Exhaust
=
0.072-0.092 in
(1.8'.""""2.3mm)
3, Valve head face to cylinder head face
depth:-
lntake
=
0.034-0.052 in
(0.86-1.32mm)
Exhaust
=
0.047-0.065 in
(1.2-1.6mm)
NOTE:
Valve inserts of 0.010 in (0.25mm)
and 0.020 in (0.5mm) oversize on diameter
are sometimes installed during manufacture.
Cylinder Heads with oversize inserts are
stamped so 10/os, so20/os, on the exhaust
manifold side in line with the valve seat con-
cerned.
Valve Seat Concentricity
1 . Dial Indicator 2. Measuring Probe
3. Check the width of the valve seat inserts
and as required reface by grinding to di-
mensions, Figure 13.
4. Measure the concentricity of valve seats,
using a dial indicator and measure con-
centricity of seat to the valve guide bore.
Total Indicator Reading should not ex-
ceed 0.002 in (0.051 mm), Figure 14.
5. Use a seat cutter to correct any seat ec-
centricity or clean up of pits and grooves.
Ensure after any rework that seat width is
within specified limits, Figure 13.
13
15
R1 - 13 .Q
Raising and Lowering of Valve Seats
1. Lowering the Valve Seat
2. Raising the Valve Seat
6. Rotate a new or refaced valve in the seat
using engineering blue, ensure all the
blue is transferred to the valve head pro-
trusion if any blue remains below or
around the seat, raise or lower the seat
accordingly, Figure 15, in the following
manner.
Lower the valve seats by removing material
from the top of seat using a:-
300 grinding wheel for, Exhaust valves and a
15° grinding wheel for, Intake valves.
Raise the valve seats by removing material
from the bottom of seat using a:-
600 grinding wheel for Exhaust valves and a
45° grinding wheel for Intake valves.
R1 -14.Q
Critical Valve Points
1. Valve Land Edge 4. Valve Face
2. Valve Head 5. Valve Stem
3. Valve Face Angle 6. Valve tip